动态代理入门

package com.dynamic;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.sql.Array;
import java.util.ArrayList;
import java.util.List;

public class TestHandler implements InvocationHandler {
	private Object proxiedObj;
	public TestHandler(Object obj){
		proxiedObj = obj;
	}
	
	public Object invoke(Object proxy, Method method, Object[] args)
			throws Throwable {
		System.out.println("1"); 
		Object obj = method.invoke(proxiedObj, args);
		System.out.println("2");
		return obj;
	}

	public static void main(String args[]){
		Hello hello = new Hello();
		Class helloClass = hello.getClass();
		IHello hello2 =(IHello)Proxy.newProxyInstance(helloClass.getClassLoader(),helloClass.getInterfaces(),new TestHandler(hello));
		hello2.sayHello();//在代理对象上调用方法时这些方法的调用会转变成对调用处理器的invoke方法的调用
	}
}
interface IHello{
	void sayHello();
}
class Hello implements IHello{
	public void sayHello(){
		System.out.println("hello world!");
	}
}

 

public static Object newProxyInstance(ClassLoader loader,
                                      Class<?>[] interfaces,
                                      InvocationHandler h)
                               throws IllegalArgumentException

     参数：

loader - 定义代理类的类加载器

interfaces - 代理类要实现的接口列表

h - 指派方法调用的调用处理程序